Method for Unlatching an Electronic Module

ABSTRACT

A method for removing an electronic module from a base where the module includes a latch extractor assembly and a stiff shift member with latch arms outside the module body and follower arms inside the module body. An extractor engages the follower arms to move the shift member laterally and move the latch arms out of engagement with the base to free the module for removal from the base.

FIELD OF THE INVENTION

The field of the invention relates to a method of removing a latched electronic module from a base.

BRIEF SUMMARY OF THE INVENTION

The invention is an improved method for unlatching an electronic module from a base. The module has two latch extractor assemblies. Each assembly includes a rigid, channel-shaped shift member at the insertion end of the module. The shift members each have a flat base with upstanding sidewalls. A latch arm on each sidewall is outside the module. A follower arm on each sidewall is inside the module. The two latch arms engage the base when the module is pushed into the base.

Each latch extractor assembly includes an extractor with a grip element away from the base and two cam surfaces which engage the two follower arms on the shift member sidewalls. Movement of the grip element away from the base moves the cam surfaces along the follower, arms to shift the base laterally and move the latch arms out of engagement with the base to release the module for removal from the base. The stiff shift member transmits unlatching forces from the follower arms to the latch arms without bending or twisting.

The module is easily unlatched and removed from the base by pulling upwardly on opposed grip elements on the extractors. Short initial upward movement of the grip elements unlatches the module. After unlatching, further upward movement of the grip elements removes the module from the base. After removal of the module, the grip elements are released and automatically return to their initial positions.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view of an electronic module mounted on a base;

FIG. 2 is a top view of FIG. 1;

FIG. 3 is a vertical sectional view taken along through one side of the module illustrating a latch and extractor assembly in the latched position;

FIG. 4 is like FIG. 3 with the assembly in the unlatched position;

FIG. 5 is an exploded view of the module;

FIGS. 6, and 7 are enlarged views of portions of FIGS. 4 and 5 showing the latched and unlatched positions of the assembly;

FIG. 8 is a sectional view along line 8-8 of FIG. 4;

FIG. 9 is a sectional view through the module along line 9-9 of FIG. 7;

FIGS. 10 and 11 are perspective views of both sides of an extractor; and

FIGS. 12 and 13 are perspective views of both sides of a latch member.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Electronic module 10 is removably mounted in recess 12 on base 14 which is typically mounted on DIN rail 16. The module 10 includes body 18 formed by two hollow molded plastic shells joined together at a circumferential seam 22 defining a hollow interior cavity 24. An electronic component 26 is mounted in cavity 24 and includes an electrical connector 28 which forms electrical connections with a complementary electrical connector (not illustrated) positioned in an opening in the bottom of recess 12 when the module is inserted into the recess, as shown in FIG. 1.

Base 14 may be a power supply base for a process fieldbus. The electronic component 26 in module 10 may be a power supply device which regulates the voltage of DC power supplied to a process fieldbus connected to the base despite variation in the voltage of the power supplied to the module. Other types of electronic components may be mounted in the module 10. The module may be mounted on other types of bases.

The module 10 is removably mounted on base 14 by two like latch extractor assemblies 30 located on opposed edges of the module. Each assembly 30 includes a molded plastic extractor 32, return coil spring 34 and metal latch member 36. Each extractor 32, shown in FIGS. 10 and 11, includes an elongate strip body 38 extending between grip element 40 on one end of the body and cam end 42 on the opposite end of the body. The grip element 40 extends out from one side of body 38 and includes a number of closely spaced grip edges or corners 44 extending along a diagonal side of the grip element. The edges 44 face down toward recess 12 and facilitate manual engagement of the elements 40 and moving of the extractors 32 away from recess 12 to unlatch and remove the module from base 14, as described below.

Spring pocket 46 is provided on strip body 38. When assemblies 30 are mounted in module 10, grip elements 40 extend outwardly from the edges of the module and pockets 46 extend inwardly toward the interior of the module. The recesses in spring pockets 46 face the upper ends of strip bodies 38 and grip elements 40.

Latch member 36, shown in FIGS. 12 and 13, is formed from flat, uniform-thickness strip metal and includes an elongate, tapered-width spring arm 48, a channel-shaped shift member 50 at the narrow lower end of arm 48 and a mounting member 52 at the wide upper end of arm 48. The width of arm 48 is tapered to reduce stress concentration. Mounting member 52 includes pairs of mounting ribs 54 extending to either side of spring arm 48.

Stiff channel-shaped shift member 50 includes a flat base 56 forming an extension of spring arm 48 and opposed sides or sidewalls 58 bent up 90 degrees to base 56 and extending upwardly from one side of the base. Angled follower arms 60 extend above sides 58 and are adjacent spring arm 48. Angled latch arms 62 extend above sides 58 and are on the end of shift member 50 away from arm 48. The angled edges of arms 60 and 62 face down, away from spring arm 48.

Latching surfaces 64 on arms 62 face up toward spring arm and are undercut to improve latching engagement with complementary, angled latch surface 66 on an inner side of base wall 74 at the bottom of recess 12, as shown in FIG. 6.

The two latch extractor assemblies 30 are identical. Each assembly is mounted on one edge of module body 18. Mounting of an assembly 30 on the right edge of the module shown in FIG. 3 will now be described, it being understood that the latch extractor assembly on the left edge of the module is similarly mounted on the module.

Latch member 36 is positioned in one open shell 20 by extending the mounting ribs 54 on one side of member 36 into recesses 70 in the shell with the arm 48 and shift member 50 extending freely in an interior channel 72 in the shell 20. See FIG. 8. The free end of shift member 50 and latch arms 62 extend through opening 76 in module bottom wall 79. The adjacent faces of the pairs of ribs 54 in recesses 70 have tight fits with the adjacent walls of recesses 70 to locate member 36 accurately in channel 72.

Extractor 32 is fitted in an elongate groove 78 extending along the side of the shell 20 holding the latch member 36. Strip body 38 is freely movable along the groove. Spring pocket 46 extends into recess 80 formed on the inner side of groove 78 with compressed spring 34 extending from the bottom of the pocket to the slotted upper wall 82 of the recess. Wall 82 is slotted to accommodate a tool holding spring 34 compressed in pocket 46 during installation of the extractor and spring into the groove 78 and recess 80. Groove 78 extends from wall 79 at the lower end of the shell to step 84 adjacent the upper end of the shell. Spring 34 normally holds extractor 32 in a down position, shown in FIG. 3, with the lower end 81 of the extractor on wall 79. See FIG. 6. Grip element 40 is normally located immediately above step 84 when extractor 32 is held in the down position shown in FIG. 3 by spring 34.

With the extractors 32 and metal latch members 36 positioned in one shell, and electronic component 26 and connector 28 positioned in the shell, the second shell is positioned over the first shell, and the two shells are moved together so that the adjacent edges of the shells abut each other. The shells include post and recess latches on their abutting edges. The latches secure the two shells together to form body 18 with the latch extractor assemblies, electronic component and connector held in place in body 18.

The cam end 42 of each extractor 32 has two angled cam surfaces 86. Surfaces 86 are on opposed sides of cam end 42. When grip elements 40 are pulled up, the cam surfaces 86 immediately engage angled follower arms 60 on shift members 50 to immediately flex the adjacent spring arms 48 inwardly and move members 50 from latched positions adjacent the outer side of the module, shown in FIGS. 3 and 6, to unlatched positions inwardly from the outer edges of the module, shown in FIGS. 4 and 7. Springs 34 are compressed and ends 81 are raised above wall 79. Spring arms 48 bias the channel members toward the latched position. Upward movement of grip elements 40 short distance 75, shown in FIG. 4, moves cam ends 42 into engagement with shift members 50 to cam members 50 inwardly, away from the adjacent sides of the module, to the unlatched or released position shown in FIGS. 4 and 7.

Assembled module 10 is latched into base 14 by extending the lower end of the module into recess 12. Lead ends 92 of shift members 50 are piloted into latch openings 68 formed through base wall 74. The angled surfaces of latch arms 62 engage the outer edges of openings 68 so that the members 50 are moved inwardly and arms 48 are flexed inwardly in channels 72 until arms 62 pass through the openings 68 and the flexed spring arms 48 move outwardly to move the latch arms 62 outwardly and under latch surfaces 66 to the latched position shown in FIGS. 3 and 6. During latching of the module onto the base, the top of the module is pushed into the recess. Connector 28 engages the connector on base 14. The arms 48 are flexed to move shift members 50 through openings 68 and to the latched positions. The extractors 32 are not used to latch the module to the base.

In order to remove a latched module from the base, an operator pulls the undersurfaces of grip elements 40 up a short distance 75 away from base 14. The edges 44 improve the operator's grip of elements 40. The initial upward movement of the grip elements 40 pulls cam ends 42 up from the position of FIG. 6 to the position of FIG. 7. Cam surfaces 86 on the opposite edges of cam ends 42 are brought immediately into engagement with the angled follower surfaces on arms 60 located on the outer sides of the upper end of shift member 50. Cam ends 42 are supported against outward movement by raised ribs 88 which are located centrally on the ends, equidistant between the two cam surfaces 86. Upward movement of cam ends 42 rotates shift member 50 inwardly and flexes spring arm 48 inwardly to move latch arms 62 inwardly a distance beyond latch surface 66 to unlatch the module from the base.

Upward movement of grip elements 40 simultaneously unlatches the two members 50 from base bottom wall 74 and, with further upward movement, withdraws the unlatched module from the base recess and disengages the connectors.

During unlatching of the module, ribs 88 on cam ends 42 engage the outer walls of grooves 78. The ribs 88 are located between the two laterally spaced cam surfaces 86, in the center of cam end 42, to support the surfaces during inward camming of shift members 50 and prevent twisting of ends 42 and members 50. The ribs 88 also space the outer surfaces 98 of strip bodies 38 from the adjacent walls of grooves 78 to reduce friction during unlatching.

Metal shift member 50, with flat base 56 and upstanding channel sides 58 has a channel-shaped cross-section and is very stiff. The stiffness of the member prevents bending of the member during unlatching when forces exerted by the cam end 42 of extractor 32 on the spaced follower arms 60 are transmitted along the length of the member 50 to move latch arms 62 on the bottom of the channel member laterally inwardly and unlatch the module. During unlatching each member 50 directly transmits unlatching forces along each L-shaped side of member 50 from an arm 60 to an arm 62 to move arms 62 inwardly away from the angled latch surfaces 66 on the bottom of the base without bending. The lateral stiffness of the channel-shaped metal shift member 50 assures that the member is not deformed laterally despite location of arms 60 outside of rib 88.

The cam end 42 of extractor 32 and shift member 50 of latch member 36 are fitted together in alignment with follower arms 60 on member 50 extending into recesses 100 formed in the sides of cam end 42. 

1. A method of unlatching an electronic module from a supporting module base comprising the steps of: A. providing an electronic module having a module body, a shift member having a rigid base, a first undercut latch arm on the rigid base outside of the module body, a first follower arm on the rigid base inside the module body, and a flexible spring arm mounting the shift member on the module body, wherein an extractor on the module body has a first cam surface engaging the follower arm; B. providing a module base having an undercut latching surface, the electronic module mounted on the base and the undercut latch arm engaging the undercut latching surface on the module base to secure the module on the base; C. moving the extractor first cam surface along the follower arm to flex the spring arm and cam the follower arm laterally; and D. transmitting lateral movement of the follower arm along the shift member and to the latch arm without bending the shift member to move the latch arm laterally and out of undercut engagement with the latching surface on the base.
 2. The method of claim 1 including the step of: E. moving the extractor cam surface away from the module base.
 3. The method of claim 2 including the steps of: F. providing a first sidewall on the rigid base with the follower arm and the latch arm on an outer edge of the first sidewall; and G. transmitting lateral movement of the follower arm through the sidewall and rigid base to the latch arm.
 4. The method of claim 3 including the steps of: H. providing a second sidewall on the rigid base and a second undercut latch arm and a second follower arm on an outer edge of the second sidewall, a second cam surface on the extractor, and a second undercut latch surface on the module base; and I. moving the extractor to move the first and second cam surfaces simultaneously away from the module base to engage the follower surfaces on the first and second sidewalls and shift the member laterally and move both undercut latch arms out of engagement with the latch surfaces without twisting the shift member.
 5. (canceled)
 6. The method of claim 1 including the steps of: E. providing a stiffening member on the shift member extending between the follower arm and the latch arm; and F. transmitting an unlatching force from the follower arm to the latch arm along both the rigid base and the stiffening member.
 7. (canceled)
 8. The method of claim 7 including the step of: I. moving the extractor away from the module base. 9-13. (canceled)
 14. A method of unlatching an electronic module from a base supporting a module comprising the steps of: A. providing a base having a first undercut latch surface; B. providing a module having a body; a latch member with a mounting end secured to the body, a rigid shift member with a first follower inside the body, and a first undercut latch arm outside the body, and a flexible spring arm between the mounting member and the rigid shift member; and an extractor having a grip element outside the body and a cam end inside the module body with a first cam surface on the cam end engageable with the shift member first follower and the first undercut latch arm engaging the first undercut latch surface to form an undercut latch connection mounting the module on the base; C. moving the grip element to shift the first cam surface along the first follower and cam the follower laterally away from the cam end without twisting while supporting the cam end against lateral movement in an opposite direction; and D. transmitting lateral movement of the first follower along the rigid shift member to the latch arm without deforming the shift member so that the first undercut latch arm is moved laterally substantially the same distance that the follower is moved laterally by the first cam surface and is out of engagement with the first undercut latch surface, and the undercut latch connection is disengaged.
 15. The method of claim 14 including the steps of: E. stiffening the shift member by providing a flat base and a side wall bent up from the flat base with the follower and the latch arm on the top of the side wall; F. moving the shift member cam surface along the top of the side wall; and G. supporting the extractor cam end on an inner surface of the body during step F. to prevent movement of the extractor cam end in the opposite direction.
 16. The method of claim 14 including the steps of: E. providing a second cam surface and a pad on the cam end of the extractor with the pad between the first and second cam surfaces. F. providing the shift member with a flat base and two spaced side walls bent up from opposite sides of the flat base with the first follower and first latch arm extending upwardly from the top of one side wall and a second follower and second latch arm extending upwardly from the top of the other side wall, and a second undercut latch arm on the base, the second latch arm engaging the second undercut latch surface; and G. camming the shift member laterally without rotating the shift member by moving the cam surfaces along the followers simultaneously. 